Corner forming apparatus and method

Abstract: A box corner forming apparatus (10) is disclosed for forming non-rectangular corners on cigarette boxes (27) and the like. A plurality of wedge-shaped spacers (14, 16) defining a plurality of parallel-sided pockets (12) are arranged around a drying drum carousel (10) for receiving opposed walls of a partly formed box having projecting side flaps (44E). A pair of folding plates (42) are provided for folding down the side flaps along corner formations defined by parallel striations (45A) between the opposed walls and the side flaps so as to form corners (44F). Corner support means in the form of a pair of retractible wedge-shaped cheek plates (28, 28A) are mounted slidably on opposite sides of the corresponding wedge-shaped spacers for supporting and maintaining the shape of the corner as it is being formed. The invention extends to a method of forming rounded or chamfered corners for a box.

Description: BACKGROUND TO THE INVENTION THIS invention relates to a corner forming apparatus and method, and in particular to a corner forming apparatus and method for the forming of corners in cigarette boxes. Nowadays, a number of cigarette boxes are manufactured with non-rectangular chamfered or rounded corners. For the sake of a neat and consistent appearance, it is important that no irregularities occur in the forming of such rounded or chamfered corners. Corners of this type are normally formed by applying a number of closely spaced parallel creases or striations to the box blank at the corner forming zone, and subsequently forming the blank into a box. A problem associated with the method is that equi-angular folding along each crease line is not assured, leading to the formation of an uneven and unattractive fold. EP-A-0 205 894 relates to a corner forming apparatus as set out in the preamble of Claim 1. However, the disclosed device employs folding dies and complemental punches and requires a dedicated filling device for filling partly formed boxes with cigarettes. In a drive for economy and efficiency, the present invention seeks to overcome disadvantages associated with these characteristics. INVENTION According to a first aspect of the invention there is provided a box corner forming apparatus as set out in Claim 1. Preferred features of this aspect of the invention are set out in Claims 2 to 7. According to a second aspect, the invention extends to a method of forming a non-rectangular corner in a box as set out in Claim 8. According to a third aspect of the invention, there is provided a method for forming a non-rectangular corner in a box as set out in Claim 9. Preferred features of this aspect of the invention are set out in Claim 10. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a side view of a corner forming apparatus of the invention incorporated into a drying drum for a hinge-lid pack cigarette box; Figure 1A shows a detailed side view of a party formed hinge-lid pack on a slide packet transfer mechanism just prior to insertion into the drying drum; Figure 2 shows an enlarged detail of the corner forming apparatus of Figure 1; Figure 3 shows a cross section on the line 3-3 of Figure 2; Figures 4A to 4C show schematic side views of the corner forming apparatus illustrating various stages in the operation thereof; and Figure 5A to 5D shows partly schematic front views of the corner forming apparatus illustrating various stages in the operation thereof. DESCRIPTION OF EMBODIMENTS Referring first to Figures 1 and 1A, a rotary drying drum 10, which forms one of the final stations in the manufacture of hinge-lid pack (HLP) cigarette boxes, receives partly folded blanks 11A from a conventional Molins slide packet transfer mechanism 11B. The transfer mechanism is mounted adjacent the drying drum, and feeds successive partly folded blanks into successive pockets 12 which are rotated past the mechanism defined between equispaced wedge-shaped spacers 14 and 16. The drying drum 10 is mounted on a central shaft 18 and is rotated stepwise so as to ensure that each successive pocket 12 is correctly aligned with the slide packet transfer. As can be seen in Figure 2, the spacer element 14 has an upper face 24 and the identical spacer element 16 has a lower face 26 which is parallel to the upper face 24 and spaced apart from the upper face 24 by a distance which allows a partly folded HLP box 27 to be retained snugly within the pocket 12, with the major rear and front walls 27A and 27B of the box contacting the respective surfaces 24 and 26, and an end wall 27C contacting a base 27D of the pocket. Mounted slidably adjacent opposite flanks of each spacer element are pairs of cheek plates 28 and 28A. When in the advanced position, the wedge-shaped cheek plates have a side profile which is identical to that of the spacer element 14 which they cover completely, as is shown at 29. Referring now to Figure 3, each cheek plate 28 is mounted slidably to the opposite sides of each spacer element by means of a tongue-and-groove arrangement 31, which allows the cheek plates to slide along a radius 32 of the drying drum. A pair of springs 34 housed within each spacer element and acting against sliding blocks 35 biases the cheek plates radially inwardly against a cam 36 carried on the drying drum, the cam being fixed as the spacer elements 14 and 16 and the cheek plates 28 move past the cam on rotary followers 39 mounted rotatably to the innermost ends of the cheek plates. A folding unit 40 extends around the spacer elements 14 and 16 and the cheek plates 28, and also remains stationary as the spacer elements rotate past it. A pair of stationary folding plates 42 are carried on the folding unit 40, and the cheek plates 28 are arranged to pass the folding plates 42 with a narrow clearance, thereby folding the box flaps at right angles to the front and rear walls of the box. With reference now to Figures 4A to 4C and 5A to 5D, the drying drum 10 works as follows. In the Figure 4A and 5A position, the partly formed hinged lid pack 27 is inserted into the pocket 12, with the pairs of cheek plates 28 and 28A of the respective spacer elements 14 and 16 being in the advanced position, in which they have a wedge-shaped side profile which is identical to that of the spacer elements. It is clear how the outermost flat profile 45 of the stationary cam 36 urges both pairs of cheek plates 28 and 28A into the advanced position. A parallel series of striations 45A are clearly visible from the detail 46A in Figure 5A. The striations are common to all of the side corners of the box. In this position, as is apparent from the detail at 46 in Figure 5A, curved corner supporting edges 47 of the cheek plates 28 and 28A are retracted and the outermost portion 47A of the corner-supporting edge 47 is coplanar with or slightly retracted relative to the planes of the upper and lower surfaces 24 and 26 of the respective spacer elements 14 and 16. In this position, the rounded corner 44A between the lower wall 44B and the lower flap 44C of the box is partly formed by the slide packet transfer. The upper flaps 44E extend transversely and have yet to be folded down. In the Figure 5B position, a more detailed front view of the corner forming apparatus is shown in which the pairs of cheek plates 28 and 28A and the spacer elements 14 and 16 have moved one more step, to a position just before the upper flaps 44E of the box are sequentially folded down by the leading edges 46A and inner faces of the stationary folding plates 42. In Figures 4B and 5C, the cheek plate 28 has travelled past the cam 36 and is forced into the retarded position by means of the spring 34. Folding of the side flaps 44E is commenced by the folding plates 42 just before the cheek plates 28 move into the retarded corner forming position. While moving to the retarded position, the corner supporting edge 47 of the wedge-shaped cheek plate 28 extends beyond the surface 26 of the spacer 16, with the curved profile acting as a support for the rounded upper corner 44F of the hinge lid pack. In this particular embodiment, the corner supporting edge 47 has a curved profile with a radius of 3.5 mm. In a position indicated in Figures 4C and 5D, the pair of cheek plates 28A have moved past the cam 36 into a retracted or retarded position, with the result that the cheek plates 28A extend over the upper surface 24 of the spacer element 14 so as to provide a corner forming support for the lower rounded corner 44A of the hinge lid pack. Opposed flaps 44C and 44E of the pack may then be sealed together, with all four side corners of the pack having the requisite degree of curvature. Naturally, the corner forming apparatus of the invention is not confined to the formation of hinge lid cigarette packs, but may be used to assist in the formation of any box corners which are not rectangular.

Claims: A box corner forming apparatus (10) comprising: a) a plurality of pocket defining elements (14, 16) defining at least one pocket (12) for receiving walls (27A, 27B) of a partly formed box (11A), at least one of the walls (27A, 27B) being formed with projecting side flaps (44E); b) folding means (40) for folding down the side flaps along corner formations (45A) defined between the walls and the side flaps so as to form non-rectangular rounded or chamfered corners (44F); and c) corner support means (28, 28A) for supporting and maintaining the shape of the corner as it is being formed; characterized in that the walls in the partly formed box are opposed parallel front and rear walls (27B, 27A), in that each pocket is defined by a pair of opposed parallel wall-contacting faces (24, 26) for receiving the opposed parallel front and rear walls (27B, 27A) of the partly-formed box, and in that the corner support means (28, 28A) is movable between a retracted feed position in which it is flush or recessed relative to the faces for allowing the partly formed box (11A) to be fed into the pocket and an extended support position in which it stands proud of the faces (24, 26) for externally supporting the corners (44F) of the box as they are being formed . A box corner forming apparatus according to claim 1 characterized in that it is supported on a carousel (10), with a plurality of pockets (12) located at spaced apart intervals around the outer periphery of the carousel (10), the wall-contacting faces (24, 26) of the pockets being defined by a plurality of spacers (14, 16) substantially wedge-shaped in form. A box corner forming apparatus according to claim 2 characterized in that the corner support means comprises pairs of wedge-shaped cheek plates (28, 28A) arranged on opposed sides of the corresponding wedge-shaped spacers (14, 16), and mounting means (31) for mounting each cheek plate slidably along a radius (32) of the carousel, the cheek plates having divergent side edges formed with the complementally profiled end faces (47) adjacent the wall-contacting faces (24, 26) of one of the corresponding spacers (14,16), actuating means (36, 39) being provided for moving the cheek plates in a radial direction relative to the carousel as the carousel (10) rotates, such that the cheek plates are moved radially outwards to the retracted feed position and radially inwards to the extended support position. A box corner forming apparatus according to claim 3 characterized in that the actuating means comprises at least one stationary cam (36), at least ore follower (39) being carried on each cheek plate for following the cam, and biasing means (34) for biasing the follower against a camming surface of the cam, with the cheek plates and spacers being arranged to rotate relative to the cam. A box corner forming apparatus according to any one of the preceding claims characterized in that the folding means comprises a folding unit (40) carrying a pair of stationary folding plates (42), and the pocket defining elements (14,16) are arranged to be rotated past the folding plates for allowing the side flaps (44E) to be folded down. A box corner forming apparatus according to any one of the claims 2 to 5 characterized in that the carousel comprises a drying drum (10) for sealing opposed flaps of partly formed prismatic hinge lid packs (11A), the drying drum being arranged to receive in series partly formed packs (11A) from a pack transfer station (11B). A box corner forming apparatus according to claim 6 characterized in that the pack transfer station (11B) is located adjacent the actuating means (36, 39), with the partly formed packs (11A) being arranged to be sequentially transferred into the pockets when the cheek plates (28, 28A) are in the feed position. A method of forming a non-rectangular corner (44F) in a box comprising the steps of: a) providing a partly formed box (11A) having front and rear walls (27B, 27A) joined by an end wall (27C) and pairs of side flaps (44C,44E) extending from the front and rear walls; b) feeding the partly formed box into a pocket (12) defined by a pair of spacers (14, 16); c) folding the side flaps (44C, 44E) down along corner formations (45A) defined between at least one of the opposed walls and a side flap so as to form non-rectangular rounded or chamfered corners (44F); and d) supporting and maintaining the shape of the corners (44F) as they are being formed using corner support means (28, 28A); characterized in that it includes the step, prior to step b), of folding the front and rear walls (27A, 27B) into a position in which they are opposed and parallel, for allowing the partly formed box to be fitted into the pocket (12), with opposed parallel front and rear walls of the box abutting against opposed parallel planar faces (24, 26) of the spacers (14, 16), and in that step d) includes the steps of moving the corner support means from a retracted feed position in which it is flush or recessed relative to the faces (24, 26) to an extended support position in which it stands proud of the faces for supporting the operatively outer faces of the corners (44A, 44F) of the box as they are being formed. A method of forming a non-rectangular corner in a box having a front wall (27B), a pair of side flaps (44E) extending laterally from the front wall and divided therefrom by a plurality of striations (45A) for defining curved or chamfered corners, an end wall (27C) joined to the front wall (27B) and an opposed rear wall (27A) extending from an opposite edge of the end wall, characterized in that the method includes the steps of folding the front and opposed rear walls (27B, 27A) towards one another to a position in which they are parallel to one another, so as to partly form a box (11A), and inserting said partly formed box into a packet-defining formation (12), with opposed parallel surfaces (24, 26) of the pocket-defining formation abutting the outer surfaces of the front wall and the opposed rear wall, subsequently folding the side flaps (44E) toward one another so as to define first and second corners (44F), and supporting the operatively outer surfaces of the first and second corners as they are being formed with complementally profiled concave corner edges (47). A method according to claim 9 characterized in that the blank of the box includes an opposed pair of side flaps (44C) extending laterally from the opposed rear wall (27A), and separated therefrom by a plurality of striations (45A), the method including the step of folding the opposed side flaps towards the front wall (27B) prior to insertion of the partly formed box into the pocket, so as to define third and fourth corners (44A), and supporting the operatively outer surfaces of the third and fourth comers during or after the formation thereof by means of complementally profiled concave corner edges (47).

Inventors: LAMM KLAUS PETER, LAMM, KLAUS PETER
Applicants: TOBACCO RES & DEV, TOBACCO RESEARCH AND DEVELOPMENT INSTITUTE LIMITED
Application year: 1994
Main classification: B31B3
IPC codes: B65D85, B31B3